Luxfer Sidewalk Prisms for Basement Lighting

In modern buildings,
architects are no longer using the old style iron gratings for areas.
Glass Prisms set in concrete on steel frames are to-day specified
by all the leading architects.

The reasons are obvious. Foremost
among them is LIGHT thrown to the rear of the basement, not wasted
at bottom of area.

Doing away with unsightly
rubbish holes below show windows, wherein there is always danger from
fire to say nothing of their unsanitary condition.

Eliminating danger of tripping
by pedestrians. They can be introduced as skylights over light-wells
or in floors to increase the light in the basement.

Testing strength of Panel

Test of Strength of Sidewalk PanelMarch 23, 1909,

Panel being made as follows:

4 ft. × 4 ft. of T bars,
1¼ in. × 1¼in. × 1/8 in.

Interlocked with channels
1½ in. × 7/16 in. × 3/16 in.

Set with our Standard Sidewalk
Prism, 4 in. × 4 in. top surface.

These were set in with
a cement mixture and allowed to stand for ten days. Then the load,
super-imposed between bearings on the panel was 2,700 lbs., and after
standing for twenty-four hours there did not appear to be any deflection
whatever.

March 24, 1909.

After twenty-four hours
of above test, 3,420 lbs. was added to above weight, making 6,120 lbs. in
all, the panel showing no deflection whatever. This test demonstrates
the fact that this panel would carry a load of over 300 lbs. to the
square foot without making any perceptible deflection.